It functions well, seems that it doesn't support a lot of my Vita games like Project Diva, Persona 4 Golden is locked and loaded. I've finished it several times before, but now I can have my friends who haven't done it, play. Which is good, because P4G is something that everyone needs to experience.

Persona is a one of a kind experience, mostly because all the of the game's side content is getting to know your friends better. Be it P3 or P4, they're both amazing. On top of that extreme amount of character development, doing so increases your powers in battle, for the other half of the massive dungeon crawling JRPG. I'd say they're both like 90 hours, and enjoyable all the way through. And by the end you'll care more about your friends than some real life people you know. Nope.

I'd compare it to pokemon if anything. There are types of attacks "Physical, Fire, Ice, Electric, Wind, ect." and there are various types of enemies that react differently. Some may just take the hit, some may take double damage from a certain attack, some may take less, some might be healed by it even. All of your teammate specialize in one or two of those, some have healing spells and such.
On top of monsters all dealing with that, you have your Personas, which are pretty much "I want this moveset", and you can switch once per turn, but each of them also all have their strengths and weaknesses. Your teammates cannot switch theirs, but you can get accessories to help protect their weaknesses.
As for the dungeon crawling itself, you wander around the dungeons freely, descending down, when you see an enemy, if you're quick about it, you can get an advantage by attacking them first, which'll let you make your move first at the beginning of combat, but they can also do the same, so you need to be wary.
Outside of combat, you can archive all of your found Personas, which you have a chance of getting after every fight. Which'll let you save them as you progress, which leads into Persona fusion, wherein you can combine persona to make a stronger one, one that will let you carry over select abilities, so if you want one to be a jack of all trades, or one with less weaknesses, you can have it.

Yes it's free, with the 1 free character changing every week or two weeks, that way you can try everyone out. You can pay for individual characters, or if you pay $40 you get everyone, and all the DLC constumes unlocked, as well as the original KI, otherwise if you just want the characters it's $20.
Season 1: Jago, Spinal, Fulgore, Orchid, Thunder, Sabrewolf, Glacius, and Sadira
Season 2 just started last month, they've got out Maya and TJ Combo already, and a newcomer named Kan Ra. They've already confirmed Riptor is coming in December, and Cinder early next year, and teased a couple other new characters that are on their way.
Season 2 is selling for the same prices ($20 and $40) but the $40 this time includes KI2.